MicroRNA (miRNA) is a single strand of ˜21-23 ribonucleotides. There are at least 2578 known human mature miRNAs (miRbase, release 20: June 2013). miRNA can regulate targeted mRNA by down-regulating mRNA levels and/or repressing translation. Thus, miRNA has greatly influenced on the field of biomedical research and diagnostics. miRNAs can function in the cell that produces them and/or be secreted into the bloodstream and function in a remote cell. As miRNAs regulate gene expression, typically their levels are tightly controlled. Deregulation of miRNAs is therefore implicated in the etiology and pathology of many diseases and disorders. Therefore, miRNAs can be used as robust biomarkers for disease diagnosis, especially for early diagnosis, staging, prognosis, and to evaluate a response in a subject to therapy or treatment.
Given at least the small size of miRNAs, they have proven difficult to accurately and quantitatively detect, which limits their usefulness in disease diagnostics. As such, there exists a need for improved miRNA detection methods for use at least in research and biomedical diagnostics.